It all depends on your definition of magic.
Building on what Reverend Bamboozle posted, I suggest that you read Satanism: The Feared Religion
by Magus Gilmore, for a clear delineation between the concepts of supernatural and super-normal. Also, since you have read The Satanic Bible, deeper study into Lesser and Greater Magic might be helpful.
Have you ever used smooth talk or calculated actions to manipulate another person? That is what Anton LaVey was referring to as Lesser Magic in The Satanic Bible. In regard to proof...your proof is that person doing what your words and actions moved them to do. I was skeptical about Greater Magic at first, and quickly realized that merely scratching the surface does the concept no justice. Study, study, study...and don't knock it until you try it.
You do not have to believe in magic, but isn't being open minded part of what drove you toward choosing to call yourself an atheist?